The present invention relates in general to ventilating apparata and in particular to exhaust vents associated with residential clothes dryers.
One aspect of either electric or gas clothes dryers which are commonly found in the home is that the hot air which is exhausted from such dryers must be routed to the outside atmosphere. In apartments and similar structures, this may be done by means of a duct which extends from the position site of the dryer up through the structure to a rooftop location. At this rooftop location, a vent hood or hat is used in order to prevent various forms of moisture and debris entering the duct and reaching the dryer. When a gas or electric dryer is installed in a home, a suitable escape route for the dryer exhaust is normally through a wall of the structure and the portion of the dryer exhaust duct which extends through the wall of the structure is fitted with a vent-type apparatus referred to as a "hood." This "hood" member overhangs and shields the end of the dryer exhaust duct so that various forms of moisture and debris will not enter. Typically such "hoods" include a flap-type member disposed over the outermost opening of the dryer exhaust duct and this flap-type member is free to swing back and forth through the end opening. One disadvantage with this type of design is that the exit location of the exhaust to the atmosphere is usually near ground level and the overhanging portion of the "hood" protrudes outwardly from the structure for several inches. This protruding distance typically complicates the mowing and trimming of the grass near the structure in the area of the "hood." A further disadvantage with such conventional hoods is that birds, animals and insects may use portions of the overhanging portion of the hood for nests, as a point of entry into the structure and for other activities. A still further disadvantage with such conventional hoods is that the flap, inasmuch as it is free to pivot back and forth, generates a "flutter" type of noise in response to outside wind blowing against it and moving it back and forth between the face of the corresponding outlet and the hood overhang. Another disadvantage with such conventional hood designs is that a flow restriction occurs by the geometry of the hood and the manner in which it blocks a portion of the opening of the dryer exhaust duct. Although such blockage may be several inches away, it does force the exhaust flow to be deflected rather than permitting a straight exiting flow direction. This bending creates a moderate back pressure flow restriction which must be overcome by the exiting exhaust in order to be free flowing. Consequently, although a three-inch or four-inch diameter dryer exhaust duct may be provided, the effective cross-sectional area of flow leaving the structure is actually less than this due to this flow restriction. A still further disadvantage of such hoods is the weight of the flap which must be overcome by exhaust pressure in order for the exhaust to escape. This also creates a flow restriction to the rate of discharge of the dryer exhaust.
It would therefore be an improvement to the design of such dryer exhaust vents to provide a lightweight vent wherein free flow from the full cross-sectional area of the dryer exhaust duct is permitted. It would also be an improvement to the design of such dryer exhaust vents if the "flutter" noise is eliminated while still providing means to block the entry of moisture and debris through the dryer exhaust duct. A still further improvement to the design of dryer exhaust vents would be to provide one with a low profile exterior with respect to the external surface of the structure so as not to protrude therefrom so that the trimming and mowing of grass would be simplified in that particular area. The invention disclosed herein provides each of these various improvements as will be described and discussed hereinafter.